1. Field Of The Invention
This invention relates to casters and primarily casters of the twin wheel type having a pair of supporting wheels on a common axle designed to support articles, such as furniture, or the like, for ready movement about a home, office, or other location and is especially concerned with such casters having braking devices for preventing rotation of the wheels when an article is located as desired.
2. Description Of The Prior Art
Heretofore, brake arrangements have been provided for casters but these have usually been of a friction type retarding mechanism designed to restrain a caster wheel against rolling. U.S. Pat. No. 2,434,863 discloses such a brake device wherein a pivoted finger is adapted to be engaged between a side portion of the caster wheel and a side wall of a casing for the caster to provide a frictional engagement wedged between the parts to restrain the wheel from rotation. U.S. Pat. No. 3,881,216 reveals a somewhat different type of brake for a caster wheel in that the braking element engages the perimeter of the wheel to effect the braking action which is initiated by a treadle member. In addition, this treadle actuates a toothed pawl vertically to engage complemental teeth on the caster to lock the caster against any swivelling movements. U.S. Pat. No. 3,914,821 discloses a caster having cup-shaped rollers on a single axle with a brake shoe adapted to engage the inner circumferential surfaces of the rollers thus providing a frictional engagement to prevent rotation of the rollers.
A centrally actuated wheel locking mechanism for hospital bed casters utilizing electromagnet devices for effecting locking action is disclosed in U.S. Pat. No. 3,890,668 wherein a movable magnetic core is operatively connected to the wheel locking catch member at each wheel and is movable vertically to engage and disengage the locking devices. U.S. Pat. No. 4,110,866 uses a pair of wheels mounted at the ends of an axle with gear like bosses on the wheel hubs which are adapted to be engaged by a toothed member which is adapted to be pushed into locking engagement with the gear teeth on the hubs by means of a lock pin against the resistance of a compression spring thereby to lock the wheels against rotation. The caster of U.S. Pat. No. 4,143,442 also uses a pair of caster wheels on a single axle and utilizes a friction braking device to both brake the wheels and retain the wheels on the axle and it should be noted that this device automatically releases when the article on which it is mounted is loaded and applies the braking action when the article is without load.
The prior art does not reveal any caster braking arrangement wherein a lever actuated locking pin engages radially disposed circumferential slots at the inner sides of a commonly mounted pair of wheels with retention means in the individual slots to retain the locking pin operatively engaged.